(118c) Use of Procedural Based Controls in Layer of Protection Analysis

The CCPS book on the layer of protection analysis (LOPA) methodology gives little credit for procedural controls. In batch operations, startups or process shutdowns, the procedural controls are often the only available means of controlling the potential hazards. This paper presents a methodology for the evaluation of procedural based controls as potential independent layers of protection (IPLs) during a LOPA study. A checklist for the evaluation of procedural controls is presented as well as an example to demonstrate the methodology.